Server cabinets are generally rectangular parallelepiped structures. The server cabinet needs to have high rigidity and strength to protect electronic equipment stored within the server cabinet. Referring to FIG. 1, a server cabinet 200 of the prior art includes a beam 201 with a plurality of plate-like structures, and each beam 201 connects two opposite sidewalls 205 of a main structure 203 for stability enhancement. However, the beam 201 occupies space within the server cabinet 200.